Bladder Tubing Wall Thickness

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sgilkey
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Bladder Tubing Wall Thickness

Post by sgilkey »

I'm trying to reduce the pressure of a bladder fuel system. ALl the bladder tubing I have been using (and for that matter, anyone else that i have bothered to notice) is 1/16 wall. I have found some 1/32 wall tubing that I am considering trying, but i have to order ten feet! So before i buy a lifetime supply I thought I'd ask, has this been tried before? Is there some reason 1/32 wall latex tubing is not suitable for a bladder fuel system?

Part of the reason I ask is that I have done a lot of experimentation with balloons of several different types and sizes and none worked well. They are definitely too thin of a wall....

Thanks guys
Scott Gilkey
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Re: Bladder Tubing Wall Thickness

Post by boiler »

In my control line days we used pen bladderd from fountain pens. Thinner than 1/32 but they held up fine. I even have an envelope of them I ordered on line two years ago when I was into wings. :cry:
Bob (Longhaul) Loescher
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Dane McGee
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Re: Bladder Tubing Wall Thickness

Post by Dane McGee »

I use the 5/16 OD x 3/16 ID x 1/16 wall thickness from McMaster Carr. I use a pressure reducer inline on all my planes, regardless of engine size and get a rock solid needle.

I don't see why The 1/32 wall wouldn't work though.

FWIW, the lowest pressure latex tubing that I have ever used was from home depot.....it was a larger diameter, maybe 3/8 with a 1/16 wall, and was really easy to use. Problem is, it was too large after filling so the bladder cavity, had to be huge. It would not work in my thin wings.


I did some tests of different tubing sizes and pressure a few years ago and found that regardless of bladder pressure, the .5 gph dripper from Home depot worked fine with every size.
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Re: Bladder Tubing Wall Thickness

Post by gsjames »

Contact Phil Cartier at Corehouse. Phil is a long-time CL Combat pilot and carries some very good bladder material. I'm sure that he has it in quantities less than 10 feet:

http://home.earthlink.net/~philcartier/
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Dane McGee
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Re: Bladder Tubing Wall Thickness

Post by Dane McGee »

Thanks for the link Gary!
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Re: Bladder Tubing Wall Thickness

Post by sgilkey »

I don't have any way to measure it, and I tried to calculate it but failed, but my GUT feeling is that the larger ID of the tubing, for a given wall thickness (say, 1/16), the pressure will go down. So 1/4" ID tubing should have lower pressure than 3/16ID of the same wall thickness. Dane, were your measurements consistent with this?
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Re: Bladder Tubing Wall Thickness

Post by boiler »

Scott, the biggest thing I found with bladders is excessive pressure that causes a problem getting a consistant run. The I/2 gal/hr drip valves was the best way to get a uniform pressure and reliable run.
Bob (Longhaul) Loescher
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Bring those planes in closer where I can see them.
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Dane McGee
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Re: Bladder Tubing Wall Thickness

Post by Dane McGee »

Scott, thats exactly right. The larger sizes will have normally have lower pressure given the wall thickness and material is the same.
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Re: Bladder Tubing Wall Thickness

Post by sgilkey »

Bob, what section of Home Depot do you get the 1/2 gph drip valves, do you have a brand or part number? thanks
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Re: Bladder Tubing Wall Thickness

Post by Dane McGee »

Home depot in the irrigation section.

Part /Locator # 37.......brown in color.


Image
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Re: Bladder Tubing Wall Thickness

Post by o1moregil »

I been using the 1 gallon/hour on my open b birds, I havent had problems, I also use the latex tubing from home depot, 6 minutes of rock solid runs, I think that the regulator is what really matters(and a good needle). Ill try some 1/2 gallon dripers to see what happens.
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Re: Bladder Tubing Wall Thickness

Post by sgilkey »

awesome, thanks guys

Scott
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Dane McGee
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Re: Bladder Tubing Wall Thickness

Post by Dane McGee »

Here is another dripper that I use. Available from Lowes, 1/2 gph
.

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Re: Bladder Tubing Wall Thickness

Post by boiler »

I have used both brands. The one from Home Depot had a longer life span.
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Bring those planes in closer where I can see them.
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sgilkey
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Re: Bladder Tubing Wall Thickness

Post by sgilkey »

5234K971 is 1/32 wall 3/16 ID latex tube, 5234K981 is 1/4 ID (McMaster). You can only get 10 or 25 foot lengths. It's about 74 cents a foot (only 55, I think, for lengths over 24 feet so get a few buddies and make a group buy). I plan to try the 1/4ID since that is the size of the fittings I have (plus i want the lower pressure) but I am concerned the thin wall will blow up to higher OD which may be too big a bulge for the wings we're using- the old 1/16 wall was already a bit bigger than the wing thickness.
Scott Gilkey
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